U.S. scientists studying "runaway" stars tossed out of our galaxy at great velocities say they've confirmed the same thing can happen to planets.

The first runaway star was discovered seven years ago, heading out of the Milky Way at 1.5 million mph, and new research says planets must be doing the same thing -- at speeds up to 30 million mph, the Harvard-Smithsonian Center for Astrophysics reported Thursday.

"These warp-speed planets would be some of the fastest objects in our galaxy," astrophysicist Avi Loeb said. "If you lived on one of them, you'd be in for a wild ride from the center of the galaxy to the universe at large."

So-called hypervelocity planets are produced in the same way as hypervelocity stars, researchers said.

A double-star system wanders too close to the supermassive black hole at the galactic center, where strong gravitational forces rip the stars from each other, sending one away at high speed while the other is captured into orbit around the black hole.

The researchers modeled what would happen if each star had an orbiting planet or two and found the star ejected outward could carry its planets along for the ride, while a star captured by the black hole could have its planets torn away and flung into interstellar space at tremendous speeds.

"Other than subatomic particles, I don't know of anything leaving our galaxy as fast as these runaway planets," study lead author Idan Ginsburg of Dartmouth College said.

It's all relativistic. At that speed our four year, nominally 1461 day, presidential term would be time dilated to 1495 days. This current term feels much longer than that, more like two terms, which would require 19/22 c speed via time dilation. Thus this ***** President beats a ***** Hole.

I imagine if you were on one of those planets it would also become very cold, very quickly.

I doubt that you would notice.

The torsional tidal forces exerted on the planet when it was torn away from its sun would be such that the mantel of the planet would be cracked like someone roll in a hard boiled egg between there palms. There would be little left on the surface of the planet uncrushed. The gravitational shear may tear the atmosphere from the planet.

14
posted on 03/23/2012 1:12:29 AM PDT
by Pontiac
(The welfare state must fail because it is contrary to human nature and diminishes the human spirit.)

Maybe some of these planets are still probably in orbit around their parent stars.

Probably not. Be lucky if the tidal forces didn't tear the planet asunder, much less let its home star keep hold of it. The reason Saturn's rings don't coalesce into moons is tidal forces, the reason the material left in the asteroid belt doesn't coalesce into a planet is tidal disruption by Jupiter. Image what the tidal forces around a black hold must be like.

It's like a game of snap-the-whip with the outboard body being tossed into the void of intergalactic space, while inboard member is trapped in orbit around the black hole. Normally, when two bodies that are not gravitationally bound interact gravitationally, their orbits will be hyperboles, with each object being deflected from its original trajectory, but never encountering each other ever again. When three or more bodies are involved, things change. For example, when a comet comes near Jupiter on its path away from the sun, one of two things can happen. If it encounters Jupiter so that it passes behind Jupiter in his orbit, the comet will be accelerated by Jupiter and tossed into a higher orbit (while slightly decelerating Jupiter and lowering his orbit). In some cases the acceleration is enough to toss the comet completely out of the solar system. If the comet passes in front of Jupiter in his orbit, the comet will be retarded, and Jupiter will increase his orbital energy. In the case of Shoemaker-Levy 9, the comet was so retarded in a 1968 pass that it was captured by Jupiter and remained in a highly elliptical orbit around Jupiter until 1994, when this unstable orbit was perturbed (possibly by one of Jupiter's moons) just enough that it collided with planet. The shredding of Shoemaker-Levy into pieces was caused by tidal forces long before the collision.

When a double star, or a planetary system (systems which are already gravitationally bound) encounter a black hole, the outcome would, it seems to me, depend on whether or not the direction of their orbit around the black hole is in the direction of their orbit around each other, or counter to it. If it is in the same direction, tidal forces will tend to tear the two asunder, stressing and possibly breaking their gravitational bond. Depending on the original trajectory and mutual orbit, one of the bodies may be tossed out to the galaxy, "by the other body", in the same way that Jupiter tosses a comet out of the solar system, and the other body will lose kinetic energy and may even become gravitationally bound to black hole.

If on the other hand, the two were orbiting opposite the direction of their encounter with the black hole, tidal forces would bind them even more firmly, at least initially, until they reached the point in their hyperbolic orbit about the black hole of closest approach, after which tidal forces would pull them apart until as they left the influence of the black hole, their orbital state would be stored to what it had been before they encountered the black hole.

22
posted on 03/23/2012 4:46:11 AM PDT
by Lonesome in Massachussets
("Jihad" is Arabic for "Helter-Skelter", "bin Laden" is Arabic for "Manson".)

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